Lets continue this discussion at the YUILibrary Forum in the thread that you started few days ago:

http://yuilibrary.com/forum/viewtopic.php?f=18&t=382&start=0

“The one major drawback to the YUI Loader is it’s need to synchronize the loading of script files. The newest browsers are introducing better parallel script downloading support; it’s useful to tap into this.”

Is that using the YUI Loader will force you into a HTTP waterfall when loading JavaScript and CSS files, and not allow newer browsers like Safari 4 (and I imagine Firefox 3.5) to use parallel or eager script loading. As it queues up the dependency resources to load, and loads them one-by-one.

Now that being said, using combo handling will help this HTTP waterfall issue tremendously. Although I’m still somewhat worried about how browsers cache the combo-handled requests as they have query-string parameters when loaded from the Yahoo CDN, something that proxies and older browsers might not cache.

1: “Conjuring YUI from thin air”
I see few benefits:
- The ability to include a 1k script (or doing it inline) to populate a your (18k script yuiloader-dom-event.js) without blocking the loading process.
- A single object will be able to insert yuiloader, setting the preferences (including custom modules) and firing the initialization process when the loader gets ready.

2: YUI Loader, drawback:
Ops, I didn’t get it. Can you elaborate on that?

3: YUI3 Modules + Custom Modules
Totally agree. For me this is the way to go in YUI 3.x.
In YUI 2.x we should have a similar approach, just for the sake of a smoothly transition. I will try to implement an advanced bootstrap object to emulate the YUI 3.x behavior on YUI 2.x.

BTW, Thanks for the feedback.

My practice over the last year or so (form whenever YUI Loader was introduced) is to have one script node on my page to seed YUI with the loader; I’ve tended to prefer the yuiloader-dom-event.js file. This script node would be followed by my application code which would assume YUI, Loader, Dom, and Event are present (via the seed file).

The one major drawback to the YUI Loader is it’s need to synchronize the loading of script files. The newest browsers are introducing better parallel script downloading support; it’s useful to tap into this.

For YUI3, I’m looking to how at my company, we can leverage loading YUI using the combo-handling feature, while also specifying our own, custom YUI3 module and their dependencies in the YUI instance config object.